Research On Wind Power Generation Based On Multiple Armature Hybrid-excitation Generator

With the increasingly serious energy shortage and environmental pollution, the development and use of wind power attract people's attention due to the wind power as a renewable green energy. Hybrid-excitation motor combines the advantages of permanent magnet motor and electric magnet motor, which main magnetic field can be adjusted and controlled with high efficiency. So the hybrid-excitation motor has broad application prospects in variable speed constant frequency wind power generation system. As wind power generation based on multiple armature hybrid-excitation generator is theme, it is carried out from theory to practice, from simulation to experiment with depth and comprehensive research. Main research contents and conclusions are as followings:(1) In order to meet the steady demand and the transient current tracking demand for three-phase grid-side converters, a new method is proposed for the inductance design. The designed inductance will be applied in the three-phase grid-connected inverter, which will put the foundation for the subsequent simulation and experiment.(2) According to the dynamic mathematical model of three-phase grid-connected inverters, using grid voltage orientation vector control, which realizes the decoupling control for the d-axis and q-axis currents and an adjustable power factor. At the same time, it is analyzed in detail how to select the switching table according to the active power error and the reactive power error. On this basis, a novel direct power control is proposed based on the new switching table.(3) According to the characteristics of the three-phase grid-connected inverter, the current predictive control, predictive control based on the error function and direct power predictive control are applied to three-phase grid-connected inverters. Inductance on-line identification will be applied to current predictive control and direct power prediction control as the predictive control is sensitive to filter inductance parameter. Finally, three kinds of predictive controls are done with simulation and experiment.(4) In order to improve the reliability and lower the cost for three-phase grid-connected inverters, the control strategy without grid voltage sensors based on phase-locked loop (PLL) and virtual grid flux is proposed. The control strategy without grid voltage sensors is used in vector control and current predictive control and verified by simulated and experimental results.(5) For the multiple armature hybrid-excitation generator, a new control that the DC voltage can be switched in parallel or series is proposed and is verified by experimental results. The paper analyzes the current circulation loop and constructs the average state model when the grid-connected inverters are operated in parallel. The circulation currents are inhibited by controlling the operation time for zero vectors at every PWM cycle when the space vector pulse width modulation (SVPWM) algorithm is used.(6) The whole experimental platform is constructed in order to do a variety of control strategies.(7) The control strategy of maximum wind power tracking is proposed based on the hybrid-excitation generator. The speed of the hybrid-excitation generator can be controlled by controlling the excitation voltage of the hybrid-excitation generator, which makes the wind turbine run at optimum tip speed ratio. Grid voltage orientation, voltage loop and current loop are used for three-phase grid-side inverters. Finally, the mode of the whole system is established in Matlab7.4 and the simulated results verify the control strategy.